Brainiac scientists tell us that the sun's made primarily of plasma, so it stands to reason that Marmot would make the Plasma 15 Down Sleeping Bag out of the same hot-hot-HOT material; unfortunately, Marmot's bag designers couldn't quite figure out how to sew plasma and magnetic fields into a functional sleeping bag, so they opted for 875-fill goose down wrapped in bulletproof Pertex Quantum fabric for the ultimate combination of warmth and lightness. The Plasma's designed to be comfortable in chilly temperatures: as low as 15 degrees, with a comfort rating of 29 degrees. It weighs less than a galaxy's worth of anti-matter—just under two pounds—and packs down smaller than the beginning of the Big Bang, so you won't notice it in your pack any more than you'd notice a few extra protons.This combination of weight and warmth is made possible by the Insotect Flow vertical baffles, which direct heat downwards to the wrap-around footbox, minimizing the amount of down required to keep you toasty. Down also loses most of its insulating value when it gets wet, so Marmot designed the Plasma an inner and outer DWR coating, and treated the insulation with Down Defender, which helps it maintain loft it things do get a little soggy. There are also small touches that make a big difference, like a cold-air defeating insulated draft tube, insulated collar, and face muff to seal your bag up tight against the chill; if you get cold, it's probably because you've taken the Plasma somewhere it doesn't quite belong, like the moon.